Anin 50 Mechanism of Action

Losartan Potassium (Anin 50), the first of a new class of antihypertensives, is an angiotensin II receptor (type AT₁) antagonist. Angiotensin II is a potent vasoconstrictor, the primary vasoactive hormone of the renin-angiotensin system and an important component in the pathophysiology of hypertension. Losartan and its principal active metabolite block the vasoconstriction and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT₁ receptor found in many tissues (e.g. vascular smooth muscle, adrenal gland). In vitro binding studies indicate that Losartan Potassium is reversible, competitive inhibitor of the AT₁ receptor. Neither Losartan nor its active metabolite inhibits ACE (kininase II, the enzyme that converts angiotensin I to angiotensin II and degrades bradykinin); nor do they bind to or block other hormone receptors or ion channels known to be important in cardiovascular regulation.